The light is connected to all 4 on some cars. If yours is one, when the light comes on ONE of the 4 wheels has hit the sensor. You only replace the brake pads on that axle. It would be front or rear. You do about 3 sets of front to one set of rear. Thank you for the question

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope
1981 280GE SWB
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